化学实验进行开放式教学的研究

通过与传统的化学实验教学模式的比较，详述了开放式教学模式的特点，并且针对实施过程中所遇到的问题提出了详尽的解决方案。     

管花蒲公英化学成分研究

目的:研究菊科管花蒲公英属Neo-Taraxacum植物管花蒲公英Neo-Taraxacum siphonathum的化学成分.方法:采用硅胶柱色谱,ODS-C_(18)反相色谱和Sephadex LH-20凝胶柱色谱以及重结晶的方法对管花蒲公英的抗氧化活性部位进行分离纯化,通过理化常数测定以及波谱分析鉴定化合物的结构.结果:从活性部位中分离并鉴定10个化合物,分别为咖啡酸(1),绿原酸(2),槲皮素(3),木犀草素(4),槲皮素-3-O-β-D-吡喃葡萄糖苷(5),槲皮素-3-O-α-D-呋喃阿拉伯糖苷(6),槲皮素-3-O-α-D-吡喃阿拉伯糖苷(7),木犀草素-7-O-β-D.吡喃葡萄糖苷(8),β-谷甾醇(9),胡萝卜苷(10).结论:该10个化合物均为首次从管花蒲公英中分离得到.     

油菜花粉的化学成分研究

目的:研究油菜花粉的化学成分.方法:采用硅胶柱色谱、Sephadex LH-20凝胶柱色谱、反相柱色谱等方法进行分离纯化,根据波谱数据进行结构鉴定.结果:从油菜花粉的醋酸乙酯和正丁醇部位分离得到9个单体化合物,分别为山柰酚-3-O-β-D-葡萄糖-(1→2)-β-D-葡萄糖苷(1),山柰酚-3,4'-双-O-β-D-葡萄糖苷(2),槲皮素-3-O-β-D-葡萄糖-(1→2)-β-D-葡萄糖苷(3),烟酸(4),烟酰胺(5),香豆酸-4-O-β-D-葡萄糖苷(6),山柰酚(7),β-谷甾醇(8),5-羟甲基糠醛(9).结论:化合物1～6均为首次从油菜花粉中分离得到.     

新型经皮渗透促进剂的研究进展

介绍国内外近年来报道的新型经皮渗透促进剂的研究与开发进展,重点介绍若干具代表性的新合成的化合物以及新发现的天然产物,包括内酰胺类、糖苷类、氨基酸衍生物、聚合物、挥发油和酶类等,为合成和发现更加安全、高效的促渗剂提供线索.     

神经肽Y对心肌蛋白质合成的影响及其意义

用~3H-亮氨酸参入法与放射免疫分析法分别测定大鼠心肌蛋白质合成速度与心脏组织中神经肽Y(NPY)含量。结果显示NPY能显著促进心肌蛋白质合成,其最大效应较去甲肾上腺素(NE)大35%,所需浓度是NE的1/100。心肌梗塞后非梗塞区组织内NPY的含量在2天时无显著改变,15天时则降低71%,提示2～15天期间该区域NPY释放增加,此为非梗塞区心肌肥大的机制之一     

Hemolytic properties and riboflavin synthesis of Helicobacter pylori: cloning and functional characterization of the ribA gene encoding GTP-cyclohydrolase II that confers hemolytic activity to Escherichia coli

Various strains of Helicobacter pylori were able to lyse erythrocytes from sheep, horse, and human when grown on blood agar. The hemolysis did not depend on the production of the vacuolating cytotoxin VacA as demonstrated by the hemolytic behavior of an isogenic vacA-negative mutant strain. The hemolytic activity could be detected in cell-free supernatants and was not regulated by iron. To isolate genes coding for proteins involved in the destruction of erythrocytes, a plasmid-based DNA library was screened for expression of lytic activity on blood agar. This approach revealed that the H. pylori ribA gene confers hemolytic properties to Escherichia coli. The ribA gene encodes the enzyme GTP-cyclohydrolase II [EC 3.5.4.25] that catalyzes the initial step in the synthesis of riboflavin. The predicted amino acid sequence of the H. pylori RibA protein showed a high degree of similarity to equivalent enzymes from microorganisms and from plants. The single gene on a plasmid restored riboflavin synthesis in a ribA mutant of E. coli and induced hemolytic activity. Furthermore, ribA overexpression was associated with the production of a fluorescent yellow molecule that was not identical with riboflavin. Hemolysis was also seen for the ribA gene from E. coli, indicating that this feature was not specific for the H. pylori gene. The presence of ribA in various H. pylori strains was confirmed by Southern blot hybridization and by polymerase chain reaction with specific primers. This analysis revealed that microdiversity exists within the DNA region upstream from ribA, which was further confirmed by nucleotide sequence analysis. Received: 25 July 1997     

地尔硫卓的合成

重点介绍了地尔硫的化学合成和拆分方法，以及近年来在其不对称合成领域的进展。     

替硝唑葡萄糖注射液的稳定性研究

采用反相ＨＰＬＣ法测定替硝唑葡萄糖注射液中替硝唑的含量，用加温加速实验研究该制剂的热稳定动力学。结果表明，替硝唑的热降解反应为一级动力学过程，在５０、６５、８０、９５℃时的降解速度常数分别为５．５８×１０－４、２．６６×１０－３、８．１０×１０－３、２．８２×１０－２ｄ－１，为８．３年，半衰期为３９．５年。     

The 2,4-dinitrophenyl group for protection of hydroxyl function of tyrosine during solid-phase peptide synthesis

The facile thiolytic cleavage of the O-2,4-dinitrophenyl (Dnp) tyrosine bond was applied to the solid-phase synthesis of the 22-amino acid residue peptide H-Asp-Ala-Val-Tyr -Thr-Gly-Leu-Asn-Thr-Arg-Asn-Gln-Glu-Thr-Tyr -Glu-Thr-Leu-Lys-His-Glu-Lys-OH, corresponding to positions 62-83 in the chain of the type 1 receptor for Fc_ε, domains expressed on the rat mucosal-type mast cells (line RBL-2H3). A method for the spectrophotometric determination of insoluble O-Dnp as well as of unprotected phenolic moieties of tyrosine was developed. It is based on monitoring S-Dnp-2-mercaptoethanol, produced upon O-Dnp thiolysis by 2-mercaptoethanol. © Munksgaard 1995. Dedicated to the memory of Dr. Susumu Funakoshi, a dear friend and a leader in peptide chemistry.     

Synthesis and Antitumour Activity of New Derivatives of Flavone-8-acetic Acid (FAA). Part 2: Ring-Substituted Derivatives

A range of 18 derivatives of flavone-8-acetic acid (FAA) with substituents on the 2-phenyl group have been prepared and their anti-tumour activity evaluated in vitro against a panel of human and murine tumour cell lines and in vivo against MAC 15A. There was no clear-cut relationship between in vitro and in vivo activity but the activity in each situation was found to be very sensitive to the precise substitution pattern with closely related isomers giving widely different activities. Some of the compounds, notably 10b,cj , and r , were active in vivo and these require further studies in order to evaluate their potential for development.